Keep w32 environment settings internal only

* src/emacs.c (main) [WINDOWSNT]: Move init_environment calls after the
set_initial_environment call.  This prevents Emacs' modifications to the
environment from contaminating Vprocess_environment and
Vinitial_environment (Bug #10980).
* src/callproc.c (getenv_internal) [WINDOWSNT]: Consult Emacs' internal
environment in as a fallback to Vprocess_environment.
* test/src/callproc-tests.el (initial-environment-preserved): New Test.

1 files changed, 14 insertions, 0 deletions

diff --git a/src/callproc.c b/src/callproc.c
index 7008b916dad..e8d089cf20e 100644
--- a/src/callproc.c
+++ b/src/callproc.c
@@ -1375,6 +1375,20 @@ getenv_internal (const char *var, ptrdiff_t varlen, char **value,
                          Vprocess_environment))
     return *value ? 1 : 0;
 
+  /* On Windows we make some modifications to Emacs' enviroment
+     without recording them in Vprocess_environment.  */
+#ifdef WINDOWSNT
+  {
+    char* tmpval = getenv (var);
+    if (tmpval)
+      {
+        *value = tmpval;
+        *valuelen = strlen (tmpval);
+        return 1;
+      }
+  }
+#endif
+
   /* For DISPLAY try to get the values from the frame or the initial env.  */
   if (strcmp (var, "DISPLAY") == 0)
     {